Seat stay and rack stay mounts for stuff?
Ran across this Tranz X pump clips to fit onto rear rack legs new in packet rack fitting (http://www.ebay.com/itm/Tranz-X-pump-clips-to-fit-onto-rear-rack-legs-new-in-packet-rack-fitting-/252229126042)
Shipping from UK is a bit much, but I've looked at that dead space between the rack and wheel...